In addition to Xbox, the episode of HBO’s hit fantasy series is available to pay-TV subscribers on the websites and free on-demand platforms of multiple cable and satellite providers during the sampling period. All episodes from previous seasons of “Game of Thrones” are currently available on HBO Go — which suffered an outage when the season-four premiere became available on Sunday night.

On TV, the “GoT” season-four premiere garnered 6.6 million viewers, according to Nielsen estimates, up 50% from the season-three opener (4.37 million) and triple the 2.2 million who watched the show’s inaugural telecast in April 2011. It was the biggest TV audience for any HBO program since the 2007 finale of “The Sopranos,” which drew 11.9 million.

The popularity of “Game of Thrones” also makes it an unprecedented target for pirates: 1.17 million unique IP addresses accessed illegal torrents of the season-four premiere within the first 15 hours of the episode popping up online, according to piracy-tracking firm Excipio. That’s more than the third-season opener in April 2013, which drew 1.15 million downloaders in the first 24 hours.

An HBO rep said the sampling deal with Microsoft for Xbox had been in the works for some time, and that it wasn’t a response to piracy estimates for the episode.

Separately, HBO on Monday posted the first episode of Mike Judge’s comedy “Silicon Valley” free on YouTube. “Silicon Valley,” a spoof of Internet startup culture, premiered Sunday following the “GoT” season-four opener. The episode will be available free on YouTube until April 28.

It would be great if HBO would make the episodes available for download through online sources like google play, iTunes, etc. I would love to be able to download then in the near term, rather than having to wait until next spring for the dvd to come out.